Some use PhD(c)
I write my name followed by my degree abbreviation, such as "John Doe, PhD" for Doctor of Philosophy.
"Society of Jesus" Jesuits use the abbreviation. The president of Loyola University Chicago uses it after his name on letters to the student body instead of PhD, though he has a PhD.
i have a PhD in....
Doctor.
The proper way to address an envelope for a Ph.D. is "Dr. [Full Name]" followed by their address.
phd on a 10 k gold ring
First, you do not use both. Typically, when work related the abbreviation follows the name. For example, John Williams MD. Or John Williams PhD.
It is Dr without a period. It is form and good manners to capitalize titles. Dr. is the abbreviation for Drive. It can also be PhD, for the highest degree in doctoring in college.
If being formal, he/she is referred to as doctor.
The proper way to list the author of a book is to write their full name as it appears on the book cover or title page, followed by their credentials (if applicable). For example, "John Smith, PhD".
The proper salutation for a psychologist is "Dr." if they hold a doctoral degree (PhD or PsyD) or "Mr." or "Ms." if they do not have a doctoral degree. It is always best to refer to them based on their level of education and preference.